This application claims benefit of Japanese Application No. 2000-306486 filed in Japan on Oct. 5, 2000, the contents of which are incorporated by this reference.
1. Field of the Invention
The present invention relates to an image projection and display device for obtaining seamless, fine, high-quality projected images using a plurality of projectors.
2. Description of the Related Art
In the prior art, there are known projection-type display devices wherein a cathode ray tube is used as a projection-type image display device which enlarges and projects an image onto a screen. Furthermore, in recent years, liquid crystal projection-type display devices using liquid crystal panels as light sources have been developed. In these liquid crystal projection-type display devices, a video signal is regenerated on a liquid crystal panel providing a two-dimensional display, light from a light source is modulated by the two-dimensional image reproduced on the aforementioned liquid crystal panel, and this light is enlarged and projected onto a screen by an optical system.
Meanwhile, in the prior art, there are also known multiscreen-type projection display devices which employ a plurality of liquid crystal projectors in order to achieve a large-screen projected image. In this system, a large screen is constituted by providing a vertical and horizontal array of a plurality of screens corresponding respectively to a plurality of projectors. However, in a multiscreen-type projection display device, each screen comprises a frame, and hence there is a problem in that the border regions between each screen are conspicuous.
Therefore, in recent years, an image projection system has been developed wherein respective projector images from a plurality of liquid crystal projectors are projected in arrayed fashion onto a single screen, thereby achieving a large-screen display. Such the image projection system is disclosed in Japanese Patent Application Laid-open No. H9-326981, which describes a method for achieving a large-screen display whereby, when projecting together images from a plurality of projectors onto a single screen, the adjoining portions of each projected image are made to overlap, in such a manner that the overlapping regions are not conspicuous, and a method for correcting geometrical distortion of the projected images due to the differences in the array positions of the respective projectors with respect to the screen.
However, the method disclosed in Japanese Patent Application Laid-open No. H9-326981 described above for calculating correction coefficients to ensure that the overlapping regions of the plurality of projected images are not conspicuous is a method which determines correction coefficients based on the assumption that the brightness level of an overlapping region can be derived by adding the respective image brightness levels for the relevant respective images which are projected individually onto the screen, and it corrects the respective projected images in the overlapping region by applying respective correction coefficients thereto. Therefore, in practice, it is not possible to ensure that uneven brightness and uneven color in the overlapping regions (joints) occurring between the images projected remain completely inconspicuous.
As described above, in an image projection system for achieving a large-screen display by projecting respective projector images for a plurality of liquid crystal projectors onto a single screen in an arrayed fashion, it has not always been possible to ensure that the overlapping regions of the plurality of projection images remain completely inconspicuous.
One object of the present invention is to provide an image projection and display device whereby, when realizing a seamless large screen using a plurality of projectors, it is possible to make uneven brightness or uneven color in the overlapping regions even less conspicuous, and hence a more seamless, finer and higher quality projected image can be achieved.
In brief, an image projection and display device according to the present invention comprises the following:
a plurality of projectors;
a projection screen forming a focusing plane for projected images from the plurality of projectors, mutually overlapping regions existing between the images;
a test image storing section for storing prescribed test images;
an image capturing section for acquiring projected test images wherein a prescribed test image is projected onto the projection screen respectively by each of the projectors;
a correction data calculating section for calculating correction data for correcting the input images for the respective projectors, on the basis of the acquired test images, in such a manner that a target brightness is achieved across the whole projection area including the overlapping regions;
a correction data storing section for storing the correction data thus calculated; and
an image correcting section for correcting the images input to the respective projectors, by using the correction data.
These objects and advantages of the present invention will become further apparent from the following detailed explantion.